/Engine/Plugins/Runtime/GeometryProcessing/Source/DynamicMesh/Public/Selections/GeometrySelectionUtil.h
For selections of typeEGeometryTopologyType::Polygroup, the results are equivalent to first converting the selection to correspondingEGeometryTopologyType::Triangleselection and then finding the boundary vertices. This gives the intuitive result for face selections, but may or may not be what is desired for polygroup vertex/edge selections, because vertices/edges that seem to be on the interior of the polygroup selection may be considered border vertices if the tesselation is such that they are adjacent to unselected triangle vertices/edges.
true if successful. For instance, could fail if GroupTopology was null for aEGeometryTopologyType::Polygroupselection
namespace UE { namespace Geometry { bool UE::Geometry::GetSelectionBoundaryVertices ( const [UE::Geometry::FDynamicMesh3](API\Runtime\GeometryCore\DynamicMesh\FDynamicMesh3) & Mesh, const [UE::Geometry::FGroupTopology](API\Plugins\DynamicMesh\FGroupTopology) * GroupTopology, const [UE::Geometry::FGeometrySelection](API\Plugins\DynamicMesh\Selections\FGeometrySelection) & ReferenceSelection, [TSet](API\Runtime\Core\Containers\TSet)< int32 > & BorderVidsOut, [TSet](API\Runtime\Core\Containers\TSet)< int32 > & CurVerticesOut ) } }